The present invention relates, in general, to couplers for mechanically connecting together adjacently disposed ends of a pair of mass transit type rail vehicles and, more particularly, the invention relates to couplers that include a drawbar/draft gear appliance that prevents damage to such vehicles and provides dissipation of energy to vehicle frames during a collision and, still more specifically, the present invention provides couplers which include extended free travel beneath the cars so that collision energy absorbing members of a car are not interfered with in a collision, the invention including further a towing feature after release mechanisms have been operative in the collision process.
Prior to the development of the present invention, mass transit type railway cars have been constructed with a soft, or collapsible, coupler apparatus so that engaging portions of the apparatus of two such railway cars may accordion, or collapse, under the force of a collision. These railway cars require couplers having a substantial distance of relief travel during collision in order to prevent damage to both the couplers and to the railway cars.
Drawbar/draft gear release mechanisms are presently used to provide the required extended free travel. The release mechanisms can include a primary shear device (bolts) to permit the railway cars to come together so that anti-climbers on the ends of the cars are effective to prevent the end of the trailing railway car from overriding the lead railway car. A secondary release mechanism can provide a telescoping drawbar to release at a higher buffing force then the primary shear device.
However, with presently existing release designs, it is not possible to tow a mass transit type railway car after the release mechanisms have functioned without the drawbar portions separating. Damaged railway cars thus have to be towed from the end opposite the collision, or be pushed, to a location where maintenance on the cars can be effected.
It is, therefore, one of the primary objects of the present invention to provide a coupler with an extended emergency release and towing feature which will allow a damaged mass transit type railway car to be towed from its damaged end after its drawbar/draft gear appliance releases.
Another object of the present invention is to provide a coupler with an extended emergency release and towing feature in which the towing can be made directly through the drawbar/draft gear appliance without having to separate damaged cars and without having to push such cars to a maintenance location.
Still another object of the present invention is to provide a coupler with an extended release travel by use of secondary release bolts, or pins, after which the above towing feature is present for moving damaged cars.
Yet another object of the present invention is to provide a coupler with an extended emergency release and towing feature in which the coupler can be readily retrofitted onto existing mass transit type railway cars.
The above objectives are accomplished, according to one embodiment of the invention, by use of a beam member located for pivotal connection to the underside of a railway vehicle and a housing slideably connected to the beam member. Cushioning means are connected to a coupling head of a car. The coupling head has a rearward extension located in the slideable housing. Primary shear means, such as bolts, extend through the walls of the housing and into the rearward extension of the cushioning means and such car coupler. Secondary shear means, such as another set of bolts, extend through the beam member and into the slideable housing. A third set of xe2x80x9cretentionxe2x80x9d bolts are located in the lower housing but have an upper portion, such as heads of the bolts, located in a horizontal slot or recess provided in the upper beam member. The slot, or recess, is forwardly terminated to provide a ledge against which the upper heads, or portions, of the retaining means can engage when the coupler head is translated forwardly, thereby pulling the lower housing with the coupler head such as when the damaged car or cars are towed. Thus, the upper head portions of the retention means in combination with the horizontal slot, or recess, and its forward edge provide means for towing after the primary and secondary shear devices have been sheared in two in a collision.